This invention relates to automatic chemical analyzers and, more particularly, to an automatic chemical analyzer in which a plurality of reaction lines are driven independently to permit chemical analysis of samples for a large number of analysis items in a short period of time.
Recently, the importance of the examination for disease diagnosis has been increasing, and also the cases and items of examination are both increasing. In order to cope with this, an automatic examination system has been desired in laboratories.
An automatic chemical analyzer provides results of analysis which are used as the important reference for diagnosis and are thus deeply related to the patient's life. To improve such automatic chemical analyzer, which is used in a hospital or like place where limited personnel and space are available, therefore, the following considerations must be paid.
(1) The quantity of sample to be extracted from the patient's body must very small lest pain should be given to the patient. Also, the quantity of a reagent to be added to the extracted sample should be very small so that the cost of analysis may be low.
(2) A number of different samples can be quickly analyzed to obtain results of analysis.
(3) The analyzer must be conveniently used so that a number of samples may be analyzed for a number of items by a limited number of personnel.
(4) The analyzer must reliably provide accurate results of analysis which are important diagnosis data concerned with the patient's life.
(5) The analyzer may be small in size so that it requires a small space.
These improvements have been remarkably achieved with prior art automatic chemical analyzers. However, because of the necessity to quickly analyze a number of different samples for a number of different items, a great number of reaction tubes to contain samples and also a great number of measuring sections are required. Therefore, there is a trend for greater size of equipment despite the demand for smaller size.
In the usual automatic chemical analyzer, a single reaction line consisting of a plurality of reaction tubes arranged in a row is provided for a single analysis item. That is, where analysis is made for 16 items, for instance, 16 reaction lines are provided. In this system, in which an equal number of reaction lines to the number of necessary analysis items are provided, the number of reaction lines is limited by the size of the equipment from the following grounds.
The length of the reaction line is dependent upon the reaction time and treatment speed. Consider now a system which has 16 reaction lines l.sub.1 to l.sub.16 each consisting of a plurality of reaction tubes A arranged in a row, as shown in FIG. 1. Suppose the interval of the reaction tubes in the same reaction line to be 25 mm, the reaction time to be 15 minutes and the treatment speed to be 90 samples per hour. Then the running speed of the reaction line is 40 seconds per sample, for the treatment speed is 90 samples per hour. The reaction time of 15 minutes means that 22.5 samples are continually on the reaction line during this time interval. This means that the length L.sub.1 of the reaction line must be at least 25.times.22.5=562.5 mm. Therefore, if it is intended to double or triple the treatment speed without reducing the reaction time, the length L.sub.1 of the reaction line has to be doubled or tripled, which is impractical. The reaction time must be at least 10 minutes from the clinical requirements although it varies with the analysis items. In addition, the number of reaction lines must increase with increasing number of analysis items. In consequence, to permit quick analysis for a great number of items very large size equipment is necessary. Furthermore, in the usual automatic chemical analyzer each reaction line is designed for an analysis item, which requires the longest reaction time from the clinical standpoint. Waste time, therefore, is inevitable with the reaction lines which are provided for analysis items requiring shorter reaction time periods, which is undesired from the standpoint of the quick analysis.